The present invention relates generally to structures and methods for securing the end of a rod, guy wire, cable or like member, and more particularly to a novel high performance attachment structure for high strength guy wires, cables, tubes and rods.
Existing attachment structures for guy wires, cables and like members include either mechanical fastening or adhesive bonding without redundancy and often fail prematurely in service at relatively low loads. Mechanical fastening normally includes crushing or crimping of the secured end of the attached member and is by itself a highly inefficient and unreliable attachment method. Adhesive bonding alone is more efficient than mechanical fastening alone, but most existing adhesives can withstand only undesirably low stress levels over extended time periods under environmental exposure.
The invention described herein solves or substantially reduces in critical importance shortcomings in existing attachment structures by providing a combination of mechanically retained and adhesively bonded end attachment fo high strength cables, guy wires, composite rods or tubes, and like members. The invention includes an elongate fitting of suitable external shape having along a central axis from one end of the fitting to the other a plurality of axial bores of successively larger diameters, the smallest bore sized to loosely receive the member to be attached. Attachment to a guy wire, cable or like member is perfected by inserting the member into the fitting, packing each annular space defined around the outer surface of the member with finely divided particulate abrasive material, injecting thermosetting or thermoplastic resin into the packed material, and curing the resin to form an adhesive bond between the abrasive material, fitting and member. Loads are transferred between the fitting and attached member by a combined mechanical lock and structural adhesive bond. The attachment structure of the invention is capable of transmitting tension, compression or torsion loads or a combination of loads, and finds utility in antenna guy wires and support cables, underwater mooring cables, composite landing gear actuation rods, torque transmitting tubes and similar applications.
It is therefore a principal object of the invention to provide an attachment structure for a high strength guy wire, cable, tube, rod or like member.
It is another object of the invention to provide a combination mechanically retained and adhesively bonded attachment structure for guy wires, cables and the like having redundant load paths.
It is a further object of the invention to provide a method for making a combination mechanically retained and adhesively bonded high strength attachment to a guy wire, cable, tube, rod or like member.
These and other objects of the invention will become apparent as the detailed description of representative embodiments proceeds.